Switching power supplies use a driver controller that turns the power switches ON and OFF. It is important that the controller not allow both power switches to be ON at the same time. So, the controller operates to turn OFF one switch before it turns ON the other, a so-called non-overlap condition. For efficient operation of the power supply, the optimum non-overlap duration that both switches are OFF depends on the specific circuit arrangement and the specific components used.
Some controllers use a constant duration non-overlap time that is sufficient for most applications. But this approach means that there will be specific circuit arrangements for which the non-overlap time duration will not be near optimal. Other controllers attempt to control the non-overlap time duration according to the specific circuit arrangement, but such approaches tend to rely on relatively complex sensing and control circuits such as complex phase-locked loops.